Jon Ossoff, the Democratic candidate in GeorgiaOs Sixth Congressional District, leaves the stage after speaking to supporters at an election night event in Sandy Springs, an Atlanta suburb, late Tuesday, April 18, 2017. Ossoff narrowly missed winning outright in the heavily conservative House district Wednesday. He will face Karen Handel, a Republican, in a runoff election in June. (Kevin D. Liles/The New York Times) ORG XMIT: XNYT116 less

Jon Ossoff, the Democratic candidate in GeorgiaOs Sixth Congressional District, leaves the stage after speaking to supporters at an election night event in Sandy Springs, an Atlanta suburb, late Tuesday, April ... more

Photo: KEVIN D. LILES

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Republican candidate for Georgia's Sixth Congressional seat Karen Handel, left, speaks at an election night watch party with husband Steve, right, in Roswell, Ga., Tuesday, April 18, 2017. Republicans are bidding to prevent a major upset in a conservative Georgia congressional district Tuesday where Democrats stoked by opposition to President Donald Trump have rallied behind a candidate who has raised a shocking amount of money for a special election. (AP Photo/David Goldman) ORG XMIT: GADG122 less

A narrow miss by a Democratic newcomer in a conservative Georgia House district has triggered a high-stakes runoff that could test President Donald Trump's influence and the limits of the backlash against him.

Democrat Jon Ossoff, a 30-year-old former congressional aide fueled by a colossal fundraising haul from out-of-state donors, came within two percentage points of an outright majority win Tuesday in an 18-candidate field in Georgia's traditionally Republican 6th Congressional District.

In second place in the special election, but lagging far behind with just under 20 percent of the vote, was Republican Karen Handel, a former Georgia secretary of state well known to voters. Handel had treated Trump gingerly in a district the president barely carried, but declared Wednesday she'd like to see him campaign for her ahead of the June 20 runoff.

"We want everybody who is supportive of Republicans, so absolutely," Handel told The Associated Press after taking a congratulatory call from Trump on Wednesday morning. "We are going to be united from this point going forward."

Trump, who attacked Ossoff in recent days as a liberal shill and mocked him for living outside of the district, crowed Wednesday on Twitter about the outcome in Georgia following Democrats' failure to win a different special election in Kansas last week.

"Dems failed in Kansas and are now failing in Georgia. Great job Karen Handel! It is now Hollywood vs. Georgia on June 20th," Trump wrote, alluding to celebrity donations that came in for Ossoff.

Still, the close outcomes in Georgia as well as conservative Kansas underscored Democrats' potential to capitalize on surging liberal energy following Trump's election, even as they pointed to the limits of how far Democrats can go in Republican-friendly districts.

Both major parties are approaching the runoff in Georgia as an important test ahead of the 2018 midterm elections. Democrats have a long-shot chance of taking back control of the House next year and breaking the GOP's monopoly control of Washington. But it will require picking up more than 20 seats and winning over droves of voters like those in the affluent, well-educated Georgia district that spans Atlanta's northern suburbs.

DuBose Porter, chairman of the Georgia Democratic Party, said the 6th District offers the perfect setting for state and national Democrats to prove their momentum heading into 2018. "If we can get over 50 percent in this district, we know we can do that statewide and around the country," Porter said, mocking Republican assertions that Ossoff failed Tuesday by falling short of an outright primary victory.

"Only the Republicans could try to define this as a defeat for the Democrats," said Porter.

At the White House, spokesman Sean Spicer tried to do exactly that. "The reaction has somewhat been, you know, that they almost won. No, they lost!" Spicer said. "They spent $8.3 million dollars and threw everything including the kitchen sink at it, and lost."

Spicer did not mention that outside Republican groups also plowed millions into attacking Ossoff and encouraging GOP turnout; a political action committee backed by House Speaker Paul Ryan and other House GOP leaders accounted for at least $2.2 million.

As for whether Trump will campaign with Handel, Spicer said: "We'll see if we're needed."